U.S. Pat. No. 5,185,117, assigned to Composite Products, Inc., describes a process for compounding thermoplastic matrix material and reinforcing fibers. This process yields a reinforced matrix material containing discrete or discontinuous reinforcing fibers. The reinforced matrix material is adapted for use in a compression molding process to form a composite part. However, due to the short lengths of the fibers in the matrix material, the strength of resulting parts is not sufficient for some desired product applications, e.g., higher performing automotive bumper beams.
It is known to add a composite material comprising a thermoplastic matrix material reinforced with a continuous strand mat into a mold to form a part. The mat reinforcing fibers are embedded within the matrix material. Because the reinforcing fibers are embedded within the matrix material, it is difficult to selectively place continuous reinforcing fibers in specific portions of a mold so as to form a part having a desired quantity and orientation of continuous reinforcing fibers in selected locations within the part.
Accordingly, there is a need for an improved molding process which produces composite parts having improved mechanical properties.